The use of peptides as targeted delivery agents is a rapidly emerging field applicable to treatment of a variety of diseases, such as cancer, metabolic diseases, inflammatory autoimmune diseases, and viral infection. Wang et al. Expert Opin. Drug Deliv. 7:159-171 (2010); Liu, Bioconjug. Chem. 20: 2199-2213 (2009); Hsu et al. BioDrugs. 23:289-304 (2009); Bellmann-Sickert et al. Trends Pharmacol. Sci. 31:434-441 (2010); Zhong, Curr. Top Med. Chem. 10:386-396 (2010); and Briand et al. Curr. Pharm. Des. 16:1136-1142 (2010). A number of cancer-targeting peptides have been identified, which specifically bind to various cancer markers, including integrin, vascular endothelial growth factor (VEGF), and heat-shock protein 90 (Hsp90). Wang et al., 2010; Hsu, 2009; and Horibe et al. J. Transl. Med. 9:8 (2011) Most of these cancer-targeting peptides have been used in the treatment of neuroendocrine tumors.
It is of great interest to develop new cancer-targeting peptides for use in diagnosing and treating a broad spectrum of cancers.